Dynamic aspects of Lon accumulation by vesicle traffic under salt stress in Arabidopsis
2009
Hamaji, K., Kobe Univ. (Japan) | Nagira, M. | Yoshida, K. | Ohnishi, M. | Oda, Y. | Uemura, T. | Goh, T. | Sato, M.H. | Morita, M.T. | Tasaka, M. | Hasezawa, S. | Nakano, A. | Hara Nishimura, I. | Maeshima, M. | Fukai, H. | Mimura, T.
The intracellular membrane dynamics of Arabidopsis cells under high salt treatment were investigated. When Arabidopsis was treated with high levels of NaCl in hydroponic culture, root tip cells showed rapid changes in the vacuolar volume, a decrease in the number of small acid compartments, active movement of vesicles and accumulation of Nasup(+) both in the central vacuole and in the vesicles around the main vacuole observed with the Nasup(+)-dependent fluorescence of Sodium Green. Detailed observation of Arabidopsis suspension-cultured cells under high salt treatment showed a similar pattern of response to that observed in root tip cells. Immunostaining of suspension-cultured cells with antibodies against AtNHX1 clearly showed the occurrence of dotted fluorescence in the cytoplasm only under salt treatment. We also confirmed the existence of AtNHXl in the vacuolar membrane isolated from suspension-cultured cells with immunofluorescence. Knockout of the vacuolar Qsub(a)-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein VAM3/SYP22 caused an increase in salt tolerance. In mutant plants, the distribution of Nasup(+) between roots and shoots differed from that of wild-type plants, with Nasup(+) accumulating more in roots and less in the shoots of the mutant plants. The role of vesicle traffic under salt stress is discussed. Hasezawa, S.
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